Portable lamp



FIG. 1 is a perspective top-side view of a portable lamp

FIG. 2 is a top view of the portable lamp

FIG. 3 is a front view of the portable lamp

FIG. 4 is a back view of the portable lamp

FIG. 5 is a left side view of the portable lamp; and,

FIG. 6 is a right side view of the portable lamp.

The dashed line shows an indefinite border. The back of the article forms no part of the claimed design. 

The ornamental design for a portable lamp, as shown and described. 